An unusual limestone rock found at an archaeological site in Croatia indicates that Neanderthals were capable of incorporating symbolic objects into their culture.

Clam-shell’ view of Side A (top) and B showing black dendrites against the background of the brown mudstone. The flake, only shown re-attached on Side A, is the result of a post-excavation fracture of the specimen. Arrows point to large inclusion visible on Sides A and B. Image credit: Davorka Radovčić et al, doi: 10.1016/j.crpv.2016.04.013.

The rock was collected more than a century ago from the Krapina Neanderthal site and was just recently analyzed by experts from the Croatian Natural History Museum, the Croatian Academy of Science and Arts and the University of Kansas.

“At the Croatian site of Krapina dated to about 130,000 years ago, among many items, a split limestone rock was excavated by Dragutin Gorjanović-Kramberger between 1899 and 1905,” the researchers said.

“Of more than 1,000 lithic items at Krapina, none resemble this specimen and we propose it was collected and not further processed by the Neanderthals because of its aesthetic attributes.”

“If we were walking and picked up this rock, we would have taken it home. It is an interesting rock,” added David Frayer, a professor emeritus of anthropology at the University of Kansas.

In 2015, Prof. Frayer and colleagues published an article about a set of eagle talons from the same Neanderthal site that included cut marks and were fashioned into a piece of jewelry.

“People have often defined Neanderthals as being devoid of any kind of aesthetic feelings, and yet we know that at this site they collected eagle talons and they collected this rock,” said Prof. Frayer, corresponding author of a paper on the discovery published in the November/December 2016 issue of the journal Comptes Rendus Palevol.

The limestone rock from the Krapina site is 9.19 cm long, 6.61 cm wide, with a maximum thickness of 1.69 cm and minimum thickness of 3.1 mm.

“The specimen is a brownish, flat piece of micritic limestone (mudstone) bearing an array of dendritic forms. The brownish color comes from the surface patina, whereas afresh break exposes the original grayish color of the rock,” Prof. Frayer and co-authors said.

“The split rock shows some irregular surfaces, but no cortex is present. Both faces are smooth and the edges are unmodified. We could find no striking platform or other areas of preparation on the rock’s edge.”

“From this, we assume the cobble was not broken apart by a Neanderthal, but was picked up in its present condition.”

“The fact that it wasn’t modified, to us, it meant that it was brought there for a purpose other than being used as a tool,” Prof. Frayer explained.

There was a small triangular flake that fits with the rock, but the break appeared to be fresh and likely happened well after the specimen was deposited into the sediments of the Krapina site. Perhaps it occurred during transport or storage after the excavation around 1900.

“The dendritic forms, ‘stem’ and veins are visually appealing and have an aesthetic quality, often appreciated by today’s rock hunters,” the scientists said.

“No one would ever suggest that Neanderthals knew the source and the meaning of the dendritic forms in rock, but there is no reason to think they would not recognize their distinctiveness and the visual appeal of them. Presumably, they considered the rock unusual and worthy of keeping.”

The team suspects a Neanderthal collected the rock from a site a few miles north of the Krapina site where there were known outcrops of biopelmicritic grey limestone. Either the Neanderthal found it there or the Krapinica stream transported it closer to the site.

“The discovery is likely minor compared with other discoveries, such as more modern humans 25,000 years ago making cave paintings in France. However, it added to a body of evidence that Neanderthals were capable assigning symbolic significance to objects and went to the effort of collecting them,” Prof. Frayer said.

The discovery could also provide more clues as to how modern humans developed these traits.